This is a very interesting thread, especially now with the Duchess of Cambridge's pregnancy. I was wondering if the unborn child is already third in line to the throne, and from reading this thread he/she is. Therefore it is already proper to say that Harry is fourth in line to the throne.

As a result, what would happen with the Council if for example (please excuse the morbid thought) if the Queen, POW and Prince William were all to die during this time that Kate is pregnant. Would Harry 'temporarily' be proclaimed King, and then at the birth of the child, cease to be King, and the infant would be proclaimed Monarch, or would the unborn child be proclaimed King/Queen - not knowing if it was King or Queen? I think its safe to assume Harry would be Regant.

I'm not sure that a fetus can be the monarch in utero, as it isn't yet a legal person. I believe that at common law, an unborn child can have a claim on inheritance to property, but the actual inheritance doesn't happen until live birth. I don't know that there is an easy answer to how this works for succession to the throne; as mentioned earlier in the thread, this was addressed by Parliament during the reign of William IV, but it was written for specific people and not as a general rule.

If the unborn child would not be proclaimed Monarch, and Harry would not be proclaimed King, would the Monarch then for a period of time 'die'? Seems contary to the idea 'The King is dead. Long Live the King (or Queen)'.

When Victoria came to the throne there was a provision that if Queen Adelaide was pregnant the Victoria would voluntarily abdicate once the child was born and a regency would be established.

That was based on the really huge "if" of Adelaide being pregnant though. As almost 200 years has passed and we can now guarantee that Catherine is pregnant it's a somewhat trickier position. They could use the precedent of the Victoria situation and establish Harry as a soon-to-abdicate King, or they could go a different way. Personally I think it would be too easy to write off Harry as making a grab for power and stealing the throne (which would be made worse by the fact that Harry would at this point legally be the regent for the child).

Instead they might go the route of having Harry as a regent from the start, only making him monarch if something happened to the baby.

If The Queen, Charles and William were all to die before the baby was born Harry would be proclaimed King as the throne can never be vacant.

He couldn't be declared Regent as their would be no monarch for him to be declared Regent for.

Whether Harry would have to ask parliament to allow him to abdicate in favour of a new baby and then act as Regent is one thing - would all the relevant parliaments agree to do so is another question altogether.

But it isn't up to one constitution and the unwritten one says that as soon as the present monarch dies the new one is in place - so Harry would automatically become King and would have to abdicate from all 16 thrones and that means all the other realms passing the necessary legislation under their own constitutions for that to happen.

All the Commonwealth realms have GGs performing the monarchs function anyway so they are not impacted by the lack of a monarch. I cannot imagine Julia Gillard or Stephen Harper complaining about an empty throne and demanding Harry be placed temporarily on the throne as King and then abdicate once Baby C draws its first breath. The public already think of this fetus as the future monarch and would not accept it being replaced by a temp King. Just do not see that happening. I can see a intergrenum with a regency or a Council of State for the few remaining weeks until the birth. I think Cameron would say he had consulted the other PMs and the Commonwealth governments were in agreement that the throne is vacant until the baby is born and Harry or some other royal is regent from now until Baby C turns 18. By the time constitutional experts and conspiracy theorists finished quibbling and debating the matter the baby would be born and the rest would be history.

It isn't a matter of their being an empty throne though - the instant the monarch dies the new one is monarch so in the unlikely scenario of The Queen, Charles and William dying before the child is born Harry is automatically King.

Your scenario suggests that there is a period of 'interregnum' when there isn't - it is instantaneous - The Queen is Dead, Long Live the King' etc etc - no time to do something that you suggest as Harry would already by King. Cameron can consult all he likes but by the time he starts consulting anyone Harry would be King - fait accompli.

Then the various governments would then have to actually formally pass the legislation to strip him of that position and he would have to sign that legislation in the UK of course.

It isn't a matter of their being an empty throne though - the instant the monarch dies the new one is monarch so in the unlikely scenario of The Queen, Charles and William dying before the child is born Harry is automatically King.

Your scenario suggests that there is a period of 'interregnum' when there isn't - it is instantaneous - The Queen is Dead, Long Live the King' etc etc - no time to do something that you suggest as Harry would already by King. Cameron can consult all he likes but by the time he starts consulting anyone Harry would be King - fait accompli.

Then the various governments would then have to actually formally pass the legislation to strip him of that position and he would have to sign that legislation in the UK of course.

If the unthinkable happened and the unborn baby of the Duke & Duchess of Cambridge was the next heir, Prince Harry would not be King nor would he automatically be declared Regent. The Council of State would step in until he or she reached their majority - the Regency would be appointed by the said Council, probably in line with the previous Monarch's wishes. There is probably a contingency plan in place to deal with such a situation.

If the unthinkable happened and the unborn baby of the Duke & Duchess of Cambridge was the next heir, Prince Harry would not be King nor would he automatically be declared Regent. The Council of State would step in until he or she reached their majority - the Regency would be appointed by the said Council, probably in line with the previous Monarch's wishes. There is probably a contingency plan in place to deal with such a situation.

No - Harry would automatically be the King if the others died before the child was born - there is no interregnum as it is automatic.

There is no Council of State. There are five Councillors of State - the first four in line of succession and the spouse of the present monarch - but they only operate when appointed by the monarch and only for the period of time specified in their appointments e.g. when The Queen is absent from the UK for a period of time she will appoint two of Charles, William, Harry and Andrew (has never appointed Philip as he has always been with her) to sign legislation and conduct the Privy Council meetings etc in her absence and only for the time of her absence. They can only be appointed by the existing monarch - so no monarch = no Councillors of State.

There is also a Privy Council that operates as the advisory body for the monarch - currently over 600 people - mainly senior politicians although senior Archbishops and Bishops of the CoE and senior judges are also appointed.

It seems that many people just don't get the instant nature of the change of monarch in the UK - at the instant The Queen dies, Charles will be King, and again from Charles to William. Thus in the unlikely situation that those three die in the next month of so Harry will be automatically King - it isn't a matter of someone saying we will discuss this, or we will have to come up with a solution or anything - it is instantaneous that Harry will be King - Britain simply has no mechanism for an interregnum.

What would then have to happen is that parliament, not only in the UK but in the other realms, would have to strip Harry of the position forcing him to abdicate.

As for a Regency - the 1937 Regency Act deals with that situation - if those ahead of the child die and the child become monarch before turning 18 the next in line over 21 is automatically Regent. The 1953 Regency Act was specific to Philip being Regent for his children but it has lapsed as he has adult children and grandchildren so it is back to the 1937 Act.

I found some discussion of this issue on this page, from officials in the 1930s who were curious about what would happen if George VI had a posthumous son. Law officers gave this opinion, at the end of a longer opinion on whether Elizabeth would be the sole heir (there was some minor concern that Elizabeth and Margaret would be joint heirs):

"We are not asked to advise on the position which would arise if on the death of a King leaving one or more daughters the Queen were pregnant. If the pregnancy terminated in the birth of a son he would be the heir. If no previous statutory provisions for dealing with the interim period between the death and the end of the pregnancy had been made, reliance would have to be placed on the inherent power of the Constitution to make necessary provisions to meet unprecedented circumstances hitherto unprovided for."

The last sentence sounds like a legalese way of saying that it would be somebody else's problem to figure out.

Edit: They were asked another question, specifically "whether a posthumous son of His Majesty would succeed to the Throne if at the demise of His Majesty there were no living male issue of His Majesty," and their response was "We have no doubt that the answer to this question is, Yes. ...It remains to consider whether legislation is necessary to authorise the succession as provided for in the Act of 1830. It might be said that as Parliament legislated and legislated ad hoc in 1830 there should be legislation now. We are however of opinion that if this is felt to be undesirable the precedent of 1830, coupled with the principle referred to on which we think it is properly based, would be sufficient authority for the succession of the Heiress Presumptive subject to defeasance if the male Heir were born."

So they were of the opinion that the living heir immediately succeeds upon the death of the previous monarch, and then immediately loses the crown upon birth of the superior heir.

I believe that the situation with Victoria was that any child of Adelaide's would succeed Victoria - not that Victoria would have to abdicate and that could still be the case here. Harry stays as King for his lifetime and the child succeeds Harry rather than William.

I believe that the situation with Victoria was that any child of Adelaide's would succeed Victoria - not that Victoria would have to abdicate and that could still be the case here. Harry stays as King for his lifetime and the child succeeds Harry rather than William.

The Regency Act of 1831 said that the birth of the child would have resulted in an immediate change:

"...the Privy Council shall, upon the Birth of such Child, without Delay, cause such Child. as the Successor entitled to the Crown of these Realms, to be openly and solemnly proclaimed, in such Manner and Form as the Kings and Queens have been usually proclaimed after the Demise of their respective Predecessors."

"...upon the Birth of such Child the Two Houses of Parliament shall forthwith assemble, and all the Laws and Regulations now in force in regard to the Meeting, the Sitting, the Continuance, the Prorogation, and the Dissolution of Parliament, and to the Continuance of the Privy Council, and of Persons in their Offices, Places, and Employments, upon the Demise of the Crown and the Accession of the Successor, shall be deemed and taken to apply to the Succession of such Child, in the same Manner as if such Child had succeeded to the Crown upon the Demise of Her Royal Highness the Princess Alexandrina Victoria, and as Her Heir."